Fluid lift pumping attachment for fluid circulating systems



June 24, 194-1. R N 2.246.845

FLUID LIFT PUMPING ATTACHMENT FOR FLUID CIRCULATING SYSTEMS Filed Feb. 26, 1938 I M V Patented June 24, 1941 NET T QFFECE FLUED LIFT PUMPING ATTACHMENT FOR 9 Claims.

This invention relates to a fluid lift pumping attachment for a fluid circulating system.

An object of the invention is to provide, in a fluid circulating system, means for utilizing the pressure of the fluid being circulated for effecting the return of the liquefied portion of the circulating medium to the compressor or other source of pressure.

The invention is illustrated in the form of an attachment for the circulating system of an air conditioner although it is applicable for general use in connection with any type of fluid circulating system.

In air conditioning systems a refrigerant, in the form of a fluid, is circulated through the system by the use of a compressor. A certain portion of the lubricating oil of the compressor is circulated with the fluid refrigerant and is gradually condensed in the condenser tank and the evaporator, or cooler tank into a liquid form. It is desirable,'and often necessary, that this liquid lubricant be taken from the tanks wherein it collects and returned to the crank case of the compressor. In the systems now in common use for I this purpose a separate pump must be employed for returning the condensed lubricant from the system to the crank case of the compressor. This pump adds considerably to the expense of installation and involves additional expense in the way of repairs.

It is an object of this invention to provide a fluid lift pumping attachment whereby the pressure of the refrigerant may be automatically utilized to return the condensed lubricant collecting in the system to the crank case of the compressor for reuse.

It is another object of the invention to provide means for the purpose specified that is of very simple construction, that will operate automatically, that will be cheap in installation and will not be liable to get out of repair.

With the above and other objects in View the invention has particular relation to certain novel features of construction, operation and arrangement of parts, an example of which is given in this specification and illustrated in the accompanying drawing, wherein the figure shows a side elevation of an air conditioner circulating system embodying the invention and shown partly in section.

Referring now more particularly to the drawing, the numeral l designates a conventional compressor and leading from the cylinders of this compressor there is a discharge line 2 which terminates in the top of the condenser drum 3. This drum is of conventional construction having the usual condenser tubes therein through which cool water may be circulated in the usual way. A fluid refrigerant is delivered under pressure by the compressor through the line 2 into the condenser drum and circulates about the cooling tubes therein whereby it is condensed, in part, into the form of liquid which collects in the bottom of the condenser drum. Mingled with this refrigerant, and in the form of vapor there is a certain amount of the lubricant which isgiven off from the compressor. As hereinabove indicated it is desirable that this lubricant be condensed to liquid form and returned to the crank case of the compressor and thereby saved.

The fluid refrigerant'and the recovered lubricant will be ultimately returned to the crank case of the compressor through the suction line 3. Leading out from the bottom of the condenser drum there is a delivery line 5 which has an oil rectifying tank 6 incorporated therein and said line 5 leads on from the rectifier tank and terminates in a manifold 1 preferably arranged above and in parallel relation with the cooling tank 8. This tank is also of conventional construction and has circulating coils therein through which the water to be cooled is circulated and from which the cooled water is delivered to the point of utilization. The manifold I has the nozzle pipes 9 leading therefrom and terminating in spray nozzles iii in the cooling tank by means of which the vaporized refrigerant and oil, coming from the condenser, are sprayed over the circulating coils in the tank 8. The delivery line is equipped with a suitable control valve I l whereby the pressure of the refrigerant delivered to the nozzles may be controlled. The suction line 4 leads from the suction manifold l2 which is connected into the domes l3, upstanding from the cooling tank 8, through the tubular branch connections 14 whereby the refrigerant, in the form of gas, collecting in the cooling tank 8 may be returned by suction to the suction line 4 and thence to the crank case of the compressor. There is a drain line Ebb leading from the bottom of the cooling tank 8 and which has an accumulator tank l6 incorporated therein with a check valve ll located in the drain line in advance of said accumulator tank. An equalizing line l5 leads from the accumulator tank and terminates in the cooling tank 8.

A return line l8 for the lubricant is connected into the accumulator tank It and its inlet end terminates near the bottom of said tank. It is formed into a coil 19 in the rectifier tank and continues on and terminates in the suction line 4 as shown. The return line It is equipped with a thermostatic expansion valve 20 for controlling the flow of the liquid therethrough and is also provided with a transparent oilsight 2| through which the flow of the lubricant may be observed.

Leading from the top of the accumulator tank and connected into the side of the condenser drum 3 there is a pressure line 22 for the admission of pressure fluid into the accumulator tank to force the lubricant contained therein through the return line !8 and into the suction line 4.

The pressure equalizing line l5 and the pressure line 22 are equipped with the respective valves 23, 24 arranged to be alternately opened and closed as hereinafter explained. Associated with these respective valves are the electromagnets 25 and 26 respectively, The valves are of such construction that they will close and remain closed and will be opened when the corresponding electromagnets are energized. The electromagnet '25 may be energized through the current conductors 27, 28 and the electromagnet 26 may be energized through the current conductors 29, 36, said conductors being connected to a suitable source of energy. The conductors 21 and 30 terminate in the spaced contacts 3|, 32 and between these contacts there is a pivotally mounted switch S3, to which the lead in conduit 34 is electrically connected. The contacts and switch may be conveniently mounted on a supporting bracket 35 which supports a float container 36. The switch 33 is extended into the container 3t and formed into an arm 3'! whose free end is overturned and carries the buoyant float 33. An equalizing line l-5a connects the top of the float chamber with the equalizing line l5 and a supply line 39 leads from the bottom of the accumulator tank l6 and is connected into the bottom of the float chamber.

As illustrated in the figure, the electromagnet 25 is energized and the valve 24 is open. The fluid in the condenser drum is under pressure, which pressure will be delivered through the line 22 into the tank 16 and will expel the lubricant which may have collected therein, out through the return line 18, which will pass through the oil rectifier 6 and be delivered to the suction line, with the returning refrigerant, into the crank case of the compressor. When the liquid lubricant is-d-ischarged from the accumulator tank 15, the level of the liquid in the float chamber will be lowered, causing the float to descend moving the switch 33 away from the contact point 32, whereupon the electromagnet 26 will be deenergized and the valve 24 will immediately close. The switch 33 will thereafter move into contact with the point 3!, completing a circuit through and energizing the electromagnet 25 thus opening the valve 23. The pressure in the accumulator tank i 5 will thus be equalized with the pressure in the drain line iEb and the condensed lubricant in the cooling tank 8 will drain down into andfill the accumulator tank Hi, the liquid also rising in the float chamber 36, whereupon the float willbe lifted and the position of the switch 33 reversed and brought into contact with the con-tact point 32 effecting the opening of the valve 24 and the closing of the valve 23 thus completing the cycle of operation.

The float construction operating the switch 33 is such that the switch will move substantially instantaneously from one contact to the other so that the closing of the valve 23 will be substantially simultaneous with the opening of the valve 24 and vice versa.

It may be noted that the oil expelled from the collector l6 will contain, mingled therewith, a certain portion of the refrigerant and the oil rectifying coil is provided for evaporating said refrigerant out of the liquid lubricant.

The drawing and description disclose what is now considered to be a preferred form of the invention by way of illustration only, while the broad principleof the invention will be defined by the appended claims.

What I claim is:

1. In combination with a closed refrigerating system of the expansion type having a compressor, condenser and cooling tank in which expansion of the high pressure refrigerant takes place, a drain conduit leading from the cooling tank adapted to drain condensed lubricating oil from the tank, valves in the drain conduit, an accumulator connected to the conduit for collecting the condensed lubricant, means for forcing the lubricant from the accumulator tank to the compressor including a pressure conduit connecting the accumulator to the high pressure refrigerant, a valve in said pressure conduit, and means for intermittently opening and closing the valve in the pressure conduit and one of the valves in the drain conduit.

2. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising an accumulator in the system for collecting lubricating oil condensed from the lower pressure refrigerant, a return conduit leading from the accumulator, means for intermittently applying the pressure of the high pressure refrigerant in the system to the collected oil and effective to expel the oil from the accumulator through the conduit.

3. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating .oil system comprising means for accumulating lubricant condensed from the low pressure refrigerant and means for intermittently applying the pressure of the high pressure refrigerant to the accumulated lubricant for expelling the lubricant from the accumulating means.

4. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes'place; a lubricating oil system comprising means in the refrigerating system for accumulating the lubricant condensed from the lower pressure refrigerant and means for intermittently applying the pressure of the high pressure refrigerant to the accumulated lubricant to return it to a source of the lubricant.

5. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising a source of supply of lubricant,

an accumulator in the system for collecting lubricant condensed from the lower pressure refrigerant, a return conduit leading from said accumulator to the source of supply, means for intermittently applying the pressure of the high pressure refrigerant in the system to the collected lubricant for returning the lubricant from the accumulator through said conduit to the source of supply.

6. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising a source of supply of lubricant, an accumulator in the system for collecting lubricant condensed from the low pressure refrigerant, a return conduit leading from the accumulator, means for intermittently applying the pressure of the high pressure refrigerant in the system tothe collected lubricant and effective to expel the lubricant from the accumulator through said conduit.

7. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising an accumulator in the system for (:01- lecting the lubricant condensed from the low pressure refrigerant, a return conduit leading from the accumulator by which the collected lubricant may be expelled, means operated in accordance with variations in the level of the lubricant in the accumulator and effective to alternately apply the pressure of the high pressure refrigerant to, and equalize said pressure in, said tank whereby the lubricant is intermittently accumulated in and expelled from the accumulator.

8. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising an accumulator in the system for collecting the lubricant condensed from the lower pressure refrigerant, a conduit through which said condensed lubricant is delivered to the accumulator, a conduit through which the collected lubricant may be expelled from the accumulator, means through which the pressure of the high pressure refrigerant may be alternately applied to the lubricant in the accumulator and equalized in the accumulator, said means including pressure and equalizing lines connected into the system and into the accumulator, electrically controlled valves for controlling said pressure and equalizing conduits and means operative in accordance with variations of the level of the lubricant in the accumulator for controlling said valves.

9. In a closed refrigerating system which operates above atmospheric pressure and having a compressor, condenser and cooling tank in which expansion of high pressure refrigerant to a lower pressure takes place; a lubricating oil system comprising an accumulator, a drain line connecting the accumulator and the cooling tank and adapted to drain the condensed lubricant from the cooling tank, a check valve in the drain line,

a pressure equalizing line connecting the accu-- mulator and the cooling tank, a return line leading from the accumulator to a source of lubricant, a pressure line connecting the accumulator with the high pressure refrigerant, a separator in the return line adapted to boil the refrigerant, from the lubricant, valves in the pressure equalizing and pressure lines, means for controlling said valves, said means being responsive to the level of the lubricant in the accumulator, whereby upon rise of the lubricant level in the accumulator, the pressure equalizing valve will be closed and the pressure valve opened, thereby expelling fluid from the accumulator through the separator and the return line, the check valve in the drain line preventing flow of the lubricant into the cooling tank, then upon lowering of the lubricant level, the pressure valve will be closed and the equalizing valve opened, whereby the lubricant may drain from the cooling tank through the drain line and into the accumulator as the lubricant condenses in the cooling tank.

ALDO E. DURDEN. 

